Incest is bad, it tends to screw up your genetical code. Thus there is a great possibility of getting handicapped (mentaly or/and physically). That is of course, only possible if you give birth to a child.

Having sexual intercourse with you sister/brother is just wrong, it has always been, and it will always be. It's gross and utterly disturbing, and if you like having sexual intercourse with you sister/brother, or even thinking about it, contact a psychologist as soon as possible.

ONTopic: If I would say it doesn't matter if you like this, I would just be disagreeing with what I just mentioned. So I say, IT'S WRONG.

I'm personally quite fond of taboo topics in fiction, so I do actually really enjoy reading incest and other related forbidden loves.
I'm an only child so it's hard to consider it as taboo as those on this forum who do, in fact, have someone (a brother or sister) they can picture when they think of the acts of incest.
I'm not in anyway promoting incest, bottomline is, manga is fiction, and I'm just in it for the story~

Incest is wrong. Plain and simple. I've had personal experience with this matter and it isn't anything to be longed over or laughed at. A sister, or brother, who does sexual things to you isn't a good thing and anyone who thinks otherwise is an ignorant fool.

there is a difference between 2d and 3d worlds though, and I draw the line a 2d....dammit i just made a horrible pun